Nonrepeat mechanism for keyboard

ABSTRACT

An encoding keyboard having individual reciprocal key-selected interposers, is constructed to eliminate the usual nonrepeat linkage while retaining the nonrepeat function. Each interposer is yieldably guided for movement within a plane, but is permitted limited lateral movement out of the plane to accomplish the nonrepeat function. Each keylever is provided with a laterally inclined cam portion. An operating interposer restores past a &#39;&#39;&#39;&#39;still depressed&#39;&#39;&#39;&#39; key by tilting laterally and thereby prevents an undesired second selection of the same interposer.

[56] References Cited UNITED STATES PATENTS 2,879,876 3/1959 Palmer et 197/16 3,001,627 9/1961 Frechette 197/17 3,014,569 12/1961 Palmer 197/98X 3,086,635 4/1963 Palmer......................... 197/16 Primary ExaminerEmest T. Wright, Jr. Attorneys-Hanifin and Jancin and E. Ronald Coffman John 0. Schaefer Lexington, Ky. Appl. No. 791,420

[22] Filed Jan. 15, 1969 [45] Patented May 11, 1971 International Business Machines Corporation Armonk, N.Y.

United States Patent [72] Inventor [73] Assignee ABSTRACT: An encoding keyboard having individual reciprocal key-selected interposers, is constructed to eliminate the usual nonrepeat linkage while retaining the non- KEYBOARD repeat function. Each interposer is yieldably guided for movement within a plane, but is permitted limited lateral movement 197/98, out of the plane to accomplish the nonrepeat function. Each 197/16 keylever is provided with a laterally inclined cam portion. An B41j 5/08 operating interposer restores past a still depressed key by 197/16, 17, 18, 98, 99

m m 3" mm m W mm NUU I 4 mum U 555 tilting laterally and thereby prevents an undesired second selection of the same interposer.

mm MAN 1 I97| 3578.133

INVENTOR. JOHN o. SCHAEFER momaavQ NONREPEA'I MECHANISM FOR KEYBOARD BAC KGROU ND OF TH E INVENTION l. Field of the Invention This invention relates to a keyboard such as that employed in an electric typewriter, and particularly to a mechanism for preventing repeated printing of a character selected by depression of a keylever.

2. Description of Prior Art Known prior single element typewriters have been provided with a keyboard which includes depressable keylevers each having an associated output interposer asshown, for example, in U.S. Pat. No. 3,086,635. By depression of a keylever, the associated interposer is moved downwardly into engagement with a power driven shaft. This shaft drives the interposer horizontally to actuate a print character selection mechanism, including a number of encoding bails. After its actuating movement, the interposer is restored to its initial position by a spring. It is usually desirable to avoid a new engagement of the interposer with the power-driven shaft in the event that the keylever is still depressed during the restore movement of the interposer. For this purpose the keylever carries a one-way pivotally mounted pawl that cooperates with' a projection of the associated interposer. As the keylever isdepressed, the projection is engaged by the pawl in a downward force transmitting direction. The keylever force moves the interposer into engaging alignment with the power-driven shaft whereby an output operation is accomplished. The interposer is restored to its initial position by a spring following the output operation. If the keylever is still held depressed during the restoring movement of the interposer, the projection of the interposer engages the pawl in the horizontal direction and pivots the pawl against the bias of a spring. This pivotal movement of the pawl allows complete restoration of the interposer while preventing its repeated engagement with the powerdriven shaft. When the keylever is released and moves to its inactive position, the pawl is returned to its unpivoted position by the bias spring. Therefore, a repetition of a specific print operation can be obtained only by releasing and redepressing the keylever.

The pawl, its pivot shaft, and its bias spring are additional parts which are necessary to be produced for and assembled.

with each keylever. In view of the high number of keylevers included in a typewriter keyboard, the pawl and bias spring nonrepeat device represents a significant element of complexity.

Accordingly, it has been a principal objective of this invention to provide an improved and greatly simplified mechanism for preventing undesired repeat keyboard output operations of a typewriter in response to a single keylever depression.

Another object of this invention has been to simplify the assembly of keyboards for typewriters by eliminating all moving parts between the keylever and its interposer.

SUMMARY OF THE INVENTION In accordance with one aspect of this invention, the interposers are mounted in a guiding means which yieldably constrains interposer movement or at least movement of significant parts of the interposer to lie within a fixed plane. Normal interposer movement involves a depressing or input displacement as accomplished by the keylever; a restore movement accomplished by a spring for returning the interposer to its initial or home position in a direction that is sufficiently transverse to the input displacement direction to allow directionally discriminatory cooperation between the interposer and the associated keylever; and an operating or output stroke occurring preferably under power between the input displacement and the restore movement of the interposer. If a keylever is retained depressed during restore movement of its associated interposer, a bent tab on the keylever coacts with the interposer to drive it from its normal plane of operation and to a position where it cannot be reengaged for displacement by the keylever. The release of the keylever allows restoration of the interposer to its normal plane of motion to permit reselection thereof by depression of the keylever.

These and other objects, features, and advantages of this invention will be apparent in the following description of a preferred embodiment of the invention. Reference is made to the accompanying drawing, in which:

FIG. 1 shows a side cross-sectional view of a typewriter keyboard provided with a nonrepeat mechanism constructed in accordance with this invention;

FIG. 2 shows an enlarged perspective illustration of a keylever and interposer employed in the keyboard of FIG. I; and

FIG. 3 shows a fragmentary top view of a portion of the keyboard shown in FIG. I.

Referring to FIG. 1, a typewriter keyboard 10 is shown, having a plurality of finger-engageable keybuttons II each mounted on an individual keylever I2. Each keylever 12 is pivoted to the typewriter frame 13 by a wire axis 13a: The basic construction of the keyboard 10 is substantially like that disclosed in aforesaid U.S. Pat. No. 3,086,635. Each of the keylevers 12 is biased upwardly by resilient means such as a leaf spring 14 to an inactive position defined by a fixedly mounted rod I5. Depression of keylever 12 moves it to an active position against a down stop 16.

A substantially rigid, power-driven output interposer 20 is carried below each keylever 12 by a-pair of fore and aft spaced-apart guide plates 30 and 31 which respectively provide a plurality of pairs of interposer receiving openings 32 and 33. A restore spring 34 is anchored to a projection 35 of plate 30 and is attached to interposer hook 21 to bias the interposer 20 upwardly and to the right in FIG. I to a home position wherein the right end 22 of the interposer 20 is retained or trapped against a leaf spring latch 22a. A selectively activatable power device or cycle clutch 40 is connected to a continuously running motor shaft (not shown), and through gears 4I,42, and 43 to a power output filter shaft 44. The cycle clutch 40 is normally held stationary by a latch 50 that engages one of two arresting ledges 45 on the clutch arbor 46. A clutch control arm SI is urged to the left by a spring 52 and tends to release latch 5 from the clutch ledge 45. Motion from the spring 52 is normally restrained by a pivoted latch 53 that engages a frame carried keeper bar 54. Latch 53 is biased upwardly to'its latching position by a spring 55. A bail or universal member 56 extends the width of the keyboard 10 and transfers downward motion from any interposer 20 to the latch 53 to release control arm 51 and latch 50, thereby initiating a l rotation of the cycle clutch 40 and power shaft 44.

A cam 47, carried by the cycle clutch 40, engages follower arm 57 of the latch 50 to restore this latch 50 and also control arm 51 to their latched positions during rotation of the cycle clutch 40. Thus, latch 50 is positioned to engage the arresting ledges 45 and disengage the clutch 40 after of rotation.

Each keylever I2 is provided with a downwardly directed projecting surface or force transfer part 17 which is normally positioned in operative alignment with an upwardly directed projecting surface or force-receiving part 23 of its associated interposer 20. When a keylever 12 is depressed, its projecting surface 17 engages the projecting surface 23 of the associated interposer 20 to pivotally displace it in the direction of path P about a support rod I8 to a position wherein the interposer end 22'is free of the leaf spring latch 22a and interposer edge 24 is positioned for engagement with one of two ledges or teeth 48 of the power shaft 44. Upon rotation of cycle clutch 40 as described above, power shaft 44 drives the selected interposer 20 leftwardly through an output stroke along path P as permitted by interposer slot 25. This displacement of the interposer 20 generates a keyboard output by permutative positioning of one or more binarily positionable output bails 26 as determined by the cooperative configuration of the bails 26 and the interposers 20 herein provided by the presence or absence of projections 27. The output permutations of the bails 26 can operate to select individual data items such as characters for printing in a typewriter as taught in U.S. Pat. No. 2,919,002, for example. The interposer 20, driven by power shaft 44, disengages by its own movement the ledges 48, and spring 34 begins to restore the interposer 20 upwardly and to the righttoward its home position along path P, as shown in FIG. 1. it is important to note that path P, is substantially transverse to the displacement P, to permit motion discrimination by the elements described below.

The nonrepeat or single-action bypass function of this invention is accomplished without the use of any components in addition to those already described.

Each interposer 20 is normally guided along its paths P, P P, by a pair of vertical coplanar surfaces 36 and 37 provided respectively by the guide plate openings 32 and 33. As shown particularly in FIGS. 2 and 3, the spring 34 is anchored to a projection 35 of the guide plate 30 that is leftwardly offset from the interposer 20. Spring 34 thus constrains normal movement of the interposer 20 to a plane defined by the surfaces 36 and 37.

Openings 32 and 33 are triangularly shaped to provide lateral clearance spaces 38 and 39 into which the interposer 20 can be displaced against the yielding resistance of its spring 34. As shown in FIG. 3, interposer-projecting surface 23 can thus be displaced laterally from its plane of normal movement to a position out of alignment with the keylever-projecting surface 17.

Actual lateral displacement of the interposer 20 is accomplished by cam-acting means provided by a forwardly facing, bent tab, or inclined portion 19 of the keylever l2 and a rearwardly facing, leading edge 28 of the interposer 20. If a keylever 12 is held depressed while its associated interposer 20 is moving along its restore path P,, interposer edge 28 will ongage or be intercepted by the inclined keylever portion 19. The interposer 20 will thus be cammed or tilted clockwise about a longitudinal axis 29 as it completes its rearward restore movement. in its tilted restored position, the interposer-projecting surface 23 is not aligned with the keyleverprojecting surface 17, but is trapped to the right side thereof as shown by the right-hand interposer 20 in FIG. 3. The depressed keylever I2 is thus made ineffective to cause a second selection of that interposer 20. Only after the keylever i2 is released will the interposer 29 be freed to be returned by spring 34 completely to its upright position in its normal plane of movement.

While the invention has been particularly shown and described with reference to a preferred embodiment thereof, it will be understood by those skilled in the art that a modification of the parts or members as well as an interchanging or reversing of the active parts of the disclosed concept are within the scope of the invention. Accordingly, the inclined portion of the cam-acting means could be provided on the interposer instead of the keylever as herein described. Having thus described a particular embodiment of my invention, l define the subject matter sought to be patented by the following claims.

lclaim'.

1. A keyboard comprising:

a plurality of keylevers each movable to either an active position or an inactive position, a finger-engageable keybutton supported by each of said keylevers, and resilient means biasing each of said keylevers toward its inactive position; a plurality of output interposers each assembled in association with one of said keylevers to be displaced thereby in a first direction from a home position upon movement of the associated keylever to its active position, and restore means for moving each interposer after being displaced, toward its said home position in a second direction transverse to said first direction;

wherein each of said keylevers and its associated interposer comprise the improvement of:

a force transfer part formed integrally with the keylever, a force-receiving part formed integrally with the interposer and being positioned in operative alignment with said force transfer part when the interposer is in its said home position, v

interposer-guiding means normally constraining movement of the interposer such that said force receiving part moves 4 substantially within a single plane including yieldable means for allowing forced deviation of the interposer from said constraint to cause displacement of said forcereceiving part from said plane, and

cam action means provided by cooperating portions of the keylever and the interposer, the keylever portionof said cam action means being positioned to intercept theinterposer portion thereof during interposer restore movement when the keylever is in its active position, and positioned to be bypassed thereby when the keylever is in its inactive position;

so that restore movement of the interposer occurring while the keylever is in its active position brings said portions of said cam action means into engagement to cause deflection of the interposer out of the normal constraint of said guiding means to displace said force-receiving portion of the interposer from said plane.

2. A keyboard as defined in claim 1 wherein the keylever portion of said cam action means comprises a bent tab formed integrally with the keylever to present an inclined surface to the interposer portion of said cam action means.

3. A keyboard as defined in claim 1 wherein said restore means comprises a restore spring individually connected to each of said interposers and oriented to urge said interposers toward their said home positions, and wherein said guiding means for each interposer comprises:

means defining a planar surface, and

said restore spring being further oriented to urge the interposer against said planar surface. V

4. A keyboard as defined in claim 3 wherein said planar surface defining means comprises a pair of spaced apart guide plates common to all said interposers, a plurality of pairs of aligned openings formed respectively in said pair of guide plates for each receiving one of said interposers, said openings of each pair including:

coplanar edge portions against which the interposer is normally urged by its restore spring, and

lateral clearance for allowing displacement of the interposer away from its normal position against said edge portions.

5. A keyboard as defined in claim 1 wherein each of said interposers is substantially rigid.

6. A keyboard comprising:

a plurality of keylevers each movable to either an active position or an inactive position, a finger-engageable keybutton supported by each of said keylevers, and resilient means biasing each of said keylevers toward its inactive position; a plurality of output interposers each assembled in association with one of said keylevers to bedisplaced thereby in a first direction from a home position, a selectively activatable, cyclically operable power device for driving any interposer displaced by its keylever through an operating stroke, universal means responsive to displacement of any interposer by its keylever for activating said power device, output means cooperatively associated with said interposers for differential operation thereby individual to said interposers upon their driven movement by said power device, and restore means operative upon termination of said operating stroke for moving each interposer toward its said home position in a second direction transverse to said first direction;

wherein each of said keylevers and its associated interposer comprise the improvement of:

a force transfer part formed integrally with the keylever, a force-receiving part formed integrally with the interposer and being positioned in operative alignment with said force transfer part when the interposer is in its said home position,

interposer guiding means normally constraining movement of the interposer such that said force-receiving part moves substantially within a single plane including yieldable means for allowing forced deviation of the interposer from said constraint to cause'displacement of said forcereceiving part from said plane, and

cam action means provided by cooperating portions of the keylever and the interposer, the keylever portion of said cam action means being positioned to intercept the.interposer portion thereof during interposer restore movement when the keylever is in its active position, and posi tioned to be bypassed thereby when the keylever is in its inactive position;

so that restore movement of the interposer occurring while the keylever is in its active position brings said portions of said cam action means into engagement to cause deflection of the interposer out of the normal constraint of said guiding means to displace said force receiving portion of the interposer from said plane.

7. A keyboard as defined in claim 6 wherein said output means comprises:

a plurality of binarily positionable encoding bails defining different items of output data by permutations of their binary positions, and i said bails and said interposers being cooperatively configured to cause said bails to be positioned in permutations individual to said interposers during driving movement thereof by said power device.

8. A keyboard as defined in claim 6 wherein the keylever portion of said cam action means comprises a bent tab formed integrally with the keylever to present an inclined surface to the interposerportion of said cam action means. I

9. A keyboard as defined in claim 6 wherein said restore means comprises a restore spring individually connected to each of said interposers and oriented to urge said interposers toward their said home positions, and wherein said guiding means for each interposer comprises:

means defining a planar surface, and

said restore spring being further oriented to urge the interposer against said planar surface.

- 10. A keyboard as defined in claim 9 wherein said planar surface defining means comprises a pair of spaced-apart guide plates common to all said interposers, a plurality of pairs of aligned openings formed respectively in said pair of guide plates for each receiving one of said interposers, said openings of each pair including: 7 I

coplanar. edge portions against which the interposer is normally urged by its restore spring. and lateral clearance for allowing displacement of the interposer away from its normal position against said edge portions. 11. A keyboard as defined in claim 6 wherein each of said interposers is substantially rigid. 

1. A keyboard comprising: a plurality of keylevers each movable to either an active position or an inactive position, a finger-engageable keybutton supported by each of said keylevers, and resilient means biasing each of said keylevers toward its inactive position; a plurality of output interposers each assembled in association with one of said keylevers to be displaced thereby in a first direction from a home position upon movement of the associated keylever to its active position, and restore means for moving each interposer after being displaced, toward its said home position in a second direction transverse to said first direction; wherein each of said keylevers and its associated interposer comprise the improvement of: a force transfer part formed integrally with the keylever, a force-receiving part formed integrally with the interposer and being positioned in operative alignment with said force transfer part when the interposer is in its said home position, interposer-guiding means normally constraining movement of the interposer such that said force receiving part moves substantially within a single plane including yieldable means for allowing forced deviation of the interposer from said constraint to cause displacement of said force-receiving part from said plane, and cam action means provided by cooperating portions of the keylever and the interposer, the keylever portion of said cam action means being positioned to intercept the interposer portion thereof during interposer restore movement when the keylever is in its active position, and positioned to be bypassed thereby when the keylever is in its inactive position; so that restore movement of the interposer occurring while the keylever is in its active position brings said portions of said cam action means into engagement to cause deflection of the interposer out of the normal constraint of said guiding means to displace said force-receiving portion of the interposer from said plane.
 2. A keyboard as defined in claim 1 wherein the keylever portion of said cam action means comprises a bent tab formed integrally with the keylever to present an inclined surface to the interposer portion of said cam action means.
 3. A keyboard as defined in claim 1 wherein said restore means comprises a restore spring individually connected to each of said interposers and oriented to urge said interposers toward their said home positions, and wherein said guiding means for each interposer comprises: means defining a planar surface, and said restore spring being further oriented to urge the interposer against said planar surface.
 4. A keyboard as defined in claim 3 wherein said planar surface defining means comprises a pair of spaced apart guide plates common to all said interposers, a plurality of pairs of aligned openings formed respectively in said pair of guide plates for each receiving one of said interposers, said openings of each pair including: coplanar edge portions against which the interposer is normally urged by its restore spring, and lateral clearance for allowing displacement of the interposer away from its normal position against said edge portions.
 5. A keyboard as defined in claim 1 wherein each of said interposers is substantially rigid.
 6. A keyboard comprising: a plurality of keylevers each movable to either an active position or an inactive position, a finger-engageable keybutton supported by each of said keylevers, and resilient means biasing each of said keylevers toward its inactive position; a plurality of output interposers each assembled in association with one of said keylevers to be displaced thereby in a first direction from a home position, a selectively activatable, cyclically operable power device for driving any interposer displaced by its keylever through an operating stroke, universal means responsive to displacement of any interposer by its keylever for activating said power device, output means cooperatively associated with said interposers for differential operation thereby individual to said interposers upon their driven movement by said power device, and restore means operative upon termination of said operating stroke for moving each interposer toward its said home position in a second direction transverse to said first direction; wherein each of said keylevers and its associated interposer comprise the improvement of: a force transfer part formed integrally with the keylever, a force-receiving part formed integrally with the interposer and being positioned in operative alignment with said force transfer part when the interposer is in its said home position, interposer guiding means normally constraining movement of the interposer such that said force-receiving part moves substantially within a single plane including yieldable means for allowing forced deviation of the interposer from said constraint to cause displacement of said force-receiving part from said plane, and cam action means provided by cooperating portions of the keylever and the interposer, the keylever portion of said cam action means being positioned to intercept the interposer portion thereof during interposer restore movement when the keylever is in its active position, and positioned to be bypassed thereby when the keylever is in its inactive position; so that restore movement of the interposer occurring while the keylever is in its active position brings said portions of said cam action means into engagement to cause deflection of the interposer out of the normal constraint of said guiding means to displace said force receiving portion of the interposer from said plane.
 7. A keyboard as defined in claim 6 wherein said output means comprises: a plurality of binarily positionable encoding bails defining different items of output data by permutations of their binary positions, and said bails and said interposers being cooperatively configured to cause said bails to be positioned in permutations individual to said interposers during driving movement thereof by said power device.
 8. A keyboard as defined in claim 6 wherein the keylever portion of said cam action means comprises a bent tab formed integrally with the keylever to present an inclined surface to the interposer portion of said cam action means.
 9. A keyboard as defined in claim 6 wherein said restore means comprises a restore spring individually connected to each of said interposers and oriented to urge said interposers toward their said home positions, and wherein said guiding means for each interposer comprises: means defining a planar surface, and said restore spring being further oriented to urge the interposer against said planar surface.
 10. A keyboard as defined in claim 9 wherein said planar surface defining means comprises a pair of spaced-apart guide plates common to all said interposers, a plurality of pairs of aligned openings formed respectively in said pair of guide plates for each receiving one of said interposers, said openings of each pair including: coplanar edge portions against which the interposer is normally urged by its restore spring, and lateral clearance for allowing displacement of the interposer away from its normal position against said edge portions.
 11. A keyboard as defined in claim 6 wherein each of said interposers is substantially rigid. 